On-spot surface enhanced Raman scattering detection of Aflatoxin B1 in peanut extracts using gold nanobipyramids evenly trapped into the AAO nanoholes

Simple, rapid, convenient, and economical surface enhanced Raman scattering (SERS) substrate is developed for on-site evaluation of Aflatoxin B₁ (AFB₁) in food matrix using handheld Raman Spectrometer. Self-assembly of gold nanobipyramids (Au NBPs) into the nanoholes of anodic aluminum oxide (AAO) template/pattern using 'drop-dry' approach provides a reliable pathway for the rapid fabrication of highly active and uniform SERS substrate. It shows enhanced and reproducible SERS signals towards the probe molecule, 4-aminothiophenol (4-ATP) with a relative standard deviation (RSD) of less than 10% and an average enhancement factor (EF) of 1 × 10⁸. For practical application, the proposed method is demonstrated for the detection of aflatoxin B₁ (AFB₁) in peanut extracts. The results show that the AFB₁ in peanut extracts can be identified within 1 min, with a limit of detection of 0.5 μg/L. Compared with conventional ELISA based AFB₁ analysis, our method is much more efficient (1 min versus >30 min).